Computed tomography characteristics of cN0 primary non-small cell lung cancer predict occult lymph node metastasis

RATIONALE

Occult lymph node metastasis (OLNM) is frequently found in patients with resectable non-small cell lung cancer (NSCLC), despite using diagnostic methods recommended by guidelines.

OBJECTIVES

To evaluate the risk of OLNM in NSCLC patients using the radiologic characteristics of the primary tumor on computed tomography (CT).

METHODS

We retrospectively reviewed clinicopathologic features of 2042 clinical T1-4N0 NSCLC patients undergoing curative intent pulmonary resection. Unique radiological features (i.e., air-bronchogram throughout the whole tumor, heterogeneous ground-glass opacity (GGO), mainly cystic appearance, endobronchial location), percentage of solid portion, and shape of tumor margin were analyzed via a stepwise approach. We used multivariable logistic regression to assess the relationship between OLNM and tumor characteristics.

RESULTS

Compared with the other unique features, endobronchial tumors were associated with the highest risk of OLNM (OR = 3.9, 95% confidence interval (CI) = 2.29-6.62), and heterogeneous GGO and mainly cystic tumors were associated with a low risk of OLNM. For tumors without unique features, the percentage of the solid portion was measured, and solid tumors were associated with OLNM (OR = 2.49, 95% CI = 1.86-3.35). Among part-solid tumors with solid proportion > 50%, spiculated margin, and peri-tumoral GGO were associated with OLNM.

CONCLUSIONS

The risk of OLNM could be assessed using radiologic characteristics on CT. This could allow us to adequately select optimal candidates for invasive nodal staging procedures (INSPs) and complete systematic lymph node dissection.

CLINICAL RELEVANCE STATEMENT

These data may be helpful for clinicians to select appropriate candidates for INSPs and complete surgical systematic lymph node dissection in NSCLC patients.

KEY POINTS

Lymph node metastasis status plays a key role in both prognostication and treatment planning. Solid tumors, particularly endobronchial tumors, were associated with occult lymph node metastasis (OLNM). The risk of OLNM can be assessed using radiologic characteristics acquired from CT images.

Beneficial implications of adjuvant chemotherapy for stage IB lung adenocarcinoma exhibiting elevated SUVmax in FDG-PET/CT: a retrospective study from a single center

Background

Controversy surrounds the efficacy of adjuvant chemotherapy (ACT) in the treatment of stage I lung adenocarcinoma (LUAD). The objective of this study was to examine the impact of the maximum standardized uptake value (SUVmax) as measured by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on the efficacy of ACT in patients diagnosed with stage I LUAD.

Methods

We scrutinized the medical records of 928 consecutive patients who underwent complete surgical resection for pathological stage I LUAD at our institution. The ideal cut-off value for primary tumor SUVmax in terms of disease-free survival (DFS) and overall survival (OS) was determined using the X-tile software. The Kaplan-Meier method and Cox regression analysis were used for survival analysis.

Results

Based on the SUVmax algorithm, the ideal cutoff values were determined to be 4.9 for DFS and 5.0 for OS. We selected 5.0 as the threshold because OS is the more widely accepted predictive endpoint. In a multivariate Cox regression analysis, SUVmax ≥ 5.0, problematic IB stage, and sublobectomy were identified as independent risk factors for poor DFS and OS. It is noteworthy that patients who were administered ACT had significantly longer DFS and OS than what was observed in the subgroup of patients with pathological stage IB LUAD and SUVmax ≥ 5.0 (p < 0.035 and p ≤ 0.046, respectively). However, there was no observed survival advantage for patients in stages IA or IB who had an SUVmax < 5.0.

Conclusion

The preoperative SUVmax of tumors served as an indicator of the impact of ACT in the context of completely resected pathological stage I LUAD. Notably, patients within the Stage IB category exhibiting elevated SUVmax levels emerged as a subgroup experiencing substantial benefits from postoperative ACT.

Prognostic role of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography with an image-based harmonization technique: A multicenter retrospective study

Objectives

Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography-based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non-small cell lung cancer.

Methods

We retrospectively examined 495 patients with clinical stage I non-small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Results

Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Conclusions

The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non-small cell lung cancers.

Wedge resection is an acceptable treatment option for radiologically low-grade lung cancer with solid predominance

OBJECTIVES

This study aimed to determine the clinical characteristics for predicting low-grade cancer in radiologically solid predominant non-small-cell lung cancer (NSCLC) and compare the survival outcomes of wedge resection with those of anatomical resection for patients with and without these characteristics.

METHODS

Consecutive patients with clinical stages IA1-IA2 NSCLC showing radiologically solid predominance ≤2 cm at 3 institutions were retrospectively evaluated. Low-grade cancer was defined as the absence of nodal involvement and blood vessel, lymphatic and pleural invasion. The predictive criteria for low-grade cancer were established by multivariable analysis. The prognosis of wedge resection was compared with that of anatomical resection for patients who met the criteria, using the propensity score-matched analysis.

RESULTS

Among 669 patients, multivariable analysis showed that ground-glass opacity (GGO) (P < 0.001) on thin-section computed tomography and an increased maximum standardized uptake value on 18-fluoro-2-deoxyglucose positron emission tomography/computed tomography (P < 0.001) were independent predictors of low-grade cancer. The predictive criteria were defined as GGO presence and maximum standardized uptake value ≤1.1 (specificity: 97.8%, sensitivity: 21.4%). In the propensity score-matched pairs (n = 189), overall survival (P = 0.41) and relapse-free survival (P = 0.18) were not significantly different between patients who underwent wedge resection and anatomical resection among those who fulfilled the criteria.

CONCLUSIONS

The radiologic criteria for GGO and a low maximum standardized uptake value could predict low-grade cancer, even in solid-dominant NSCLC sized ≤2 cm. Wedge resection could be an acceptable surgical option for patients with radiologically predicted indolent NSCLC showing a solid-dominant appearance.

Histopathologic Basis for a Chest CT Deep Learning Survival Prediction Model in Patients with Lung Adenocarcinoma

Background A preoperative CT-based deep learning (DL) prediction model was proposed to estimate disease-free survival in patients with resected lung adenocarcinoma. However, the black-box nature of DL hinders interpretation of its results. Purpose To provide histopathologic evidence underpinning the DL survival prediction model and to demonstrate the feasibility of the model in identifying patients with histopathologic risk factors through unsupervised clustering and a series of regression analyses. Materials and Methods For this retrospective study, data from patients who underwent curative resection for lung adenocarcinoma without neoadjuvant therapy from January 2016 to September 2020 were collected from a tertiary care center. Seven histopathologic risk factors for the resected adenocarcinoma were documented: the aggressive adenocarcinoma subtype (cribriform, morular, solid, or micropapillary-predominant subtype); mediastinal nodal metastasis (pN2); presence of lymphatic, venous, and perineural invasion; visceral pleural invasion (VPI); and EGFR mutation status. Unsupervised clustering using 80 DL model-driven CT features was performed, and associations between the patient clusters and the histopathologic features were analyzed. Multivariable regression analyses were performed to investigate the added value of the DL model output to the semantic CT features (clinical T category and radiologic nodule type [ie, solid or subsolid]) for histopathologic associations. Results A total of 1667 patients (median age, 64 years [IQR, 57-71 years]; 975 women) were evaluated. Unsupervised patient clusters 3 and 4 were associated with all histopathologic risk factors (P < .01) except for EGFR mutation status (P = .30 for cluster 3). After multivariable adjustment, model output was associated with the aggressive adenocarcinoma subtype (odds ratio [OR], 1.03; 95% CI: 1.002, 1.05; P = .03), venous invasion (OR, 1.03; 95% CI: 1.004, 1.06; P = .02), and VPI (OR, 1.08; 95% CI: 1.06, 1.10; P < .001), independently of the semantic CT features. Conclusion The deep learning model extracted CT imaging surrogates for the histopathologic profiles of lung adenocarcinoma. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Yanagawa in this issue.

Early diagnosis of breast cancer lung metastasis by nanoprobe-based luminescence imaging of the pre-metastatic niche

BACKGROUND

Early detection of breast cancer lung metastasis remains highly challenging, due to few metastatic cancer cells at an early stage. Herein we propose a new strategy for early diagnosis of lung metastasis of breast cancer by luminescence imaging of pulmonary neutrophil infiltration via self-illuminating nanoprobes.

METHODS

Luminescent nanoparticles (LAD NPs) were engineered using a biocompatible, neutrophil-responsive self-illuminating cyclodextrin material and an aggregation-induced emission agent. The chemiluminescence resonance energy transfer (CRET) effect and luminescence properties of LAD NPs were fully characterized. Using mouse peritoneal neutrophils, in vitro luminescence properties of LAD NPs were thoroughly examined. In vivo luminescence imaging and correlation analyses were performed in mice inoculated with 4T1 cancer cells. Moreover, an active targeting nanoprobe was developed by surface decoration of LAD NPs with a neutrophil-targeting peptide, which was also systemically evaluated by in vitro and in vivo studies.

RESULTS

LAD NPs can generate long-wavelength and persistent luminescence due to the CRET effect. In a mouse model of 4T1 breast cancer lung metastasis, we found desirable correlation between neutrophils and tumor cells in the lungs, demonstrating the effectiveness of early imaging of the pre-metastatic niche by the newly developed LAD NPs. The active targeting nanoprobe showed further enhanced luminescence imaging capability for early detection of pulmonary metastasis. Notably, the targeting nanoprobe-based luminescence imaging strategy remarkably outperformed PET/CT imaging modalities in the examined mouse model. Also, preliminary tests demonstrated good safety of LAD NPs.

CONCLUSIONS

The neutrophil-targeting imaging strategy based on newly developed luminescence nanoparticles can serve as a promising modality for early diagnosis of lung metastasis of breast cancers.

Identification of High-Risk of Recurrence in Clinical Stage I Non-Small Cell Lung Cancer

Objective

This study aimed to identify patients at a high risk of recurrence using preoperative high-resolution computed tomography (HRCT) in clinical stage I non-small cell lung cancer (NSCLC).

Methods

A total of 567 patients who underwent screening and 1,216 who underwent external validation for clinical stage I NSCLC underwent lobectomy or segmentectomy. Staging was used on the basis of the 8^th edition of the tumor–node–metastasis classification. Recurrence-free survival (RFS) was estimated using the Kaplan–Meier method, and the multivariable Cox proportional hazards model was used to identify independent prognostic factors for RFS.

Results

A multivariable Cox analysis identified solid component size (hazard ratio [HR], 1.66; 95% confidence interval [CI] 1.30–2.12; P < 0.001) and pure solid type (HR, 1.82; 95% CI 1.11–2.96; P = 0.017) on HRCT findings as independent prognostic factors for RFS. When patients were divided into high-risk (n = 331; solid component size of >2 cm or pure solid type) and low-risk (n = 236; solid component size of ≤2 cm and part solid type) groups, there was a significant difference in RFS (HR, 5.33; 95% CI 3.09–9.19; 5-year RFS, 69.8% vs. 92.9%, respectively; P < 0.001). This was confirmed in the validation set (HR, 5.32; 95% CI 3.61–7.85; 5-year RFS, 72.0% vs. 94.8%, respectively; P < 0.001).

Conclusions

In clinical stage I NSCLC, patients with a solid component size of >2 cm or pure solid type on HRCT were at a high risk of recurrence.

Narrative review of optimal prognostic radiological tools using computed tomography for T1N0-staged non-small cell lung cancer

Various radiological tools can predict the prognosis of non-small cell lung cancer (NSCLC). In this study, we evaluated the prognostic effect of different radiological tools such as whole tumor size (WTS), consolidation size (CS), consolidation tumor ratio (CTR), tumor disappearance ratio (TDR), mediastinal diameter (MD), and ground glass opacity (GGO) using high-resolution computed tomography (HRCT). We reviewed recent retrospective studies on the predictive effect of these radiological tools on disease-free survival (DFS) and overall survival (OS) in patients with T1N0-staged NSCLC. We searched PubMed and the British Library databases for the English literature published from January 2010 to December 2020 and generated a total of 32 publications (NSCLC, n=16; adenocarcinoma, n=16). The TNM classification version 7 was used in 18 studies, and version 8 in 14 studies. The evaluated radiological parameters were WTS, CS including T category, CTR, TDR, MD, presence of GGO, GGO ratio, and pure GGO. This review suggested that CS, MD, and the presence of GGO are optimal prognostic radiological tools for cT1N0-Staged NSCLC. CTR or TDR for part solid nodules (PSNs) is not a well-accepted prognostic factor. Further investigations are required to differentiate between benign scars and malignant components on HRCT and evaluate the prognosis of PSNs (1< CS ≤2 cm) with large WTS in the future.

Primary Tumor Resection Improves Survival for EGFR-TKI-Treated Patients With Occult M1a Lung Adenocarcinoma

Background

The role of primary tumor resection in occult M1a lung adenocarcinoma remains unclear, especially for patients receiving targeted therapy. The purpose of this study is to assess the effect of primary tumor resection on overall survival (OS) in lung adenocarcinoma patients with occult pleural disseminations receiving targeted therapy.

Methods

Lung adenocarcinoma patients with intraoperatively-confirmed occult pleural dissemination (M1a), who hospitalized in the Department of Thoracic Surgery in Fudan Shanghai Cancer Center from May 2008 to December 2017 and received EGFR-TKIs therapy, were enrolled. Log-rank tests were used to compare the survival differences between groups.

Results

34 patients receiving EGFR-TKIs were enrolled. The majority of them were never smokers (29/34, 85.3%). Among the enrolled patients, 20 (58.8%) patients underwent primary tumor resection, while 14 (41.2%) patients not. There was no distributional difference of baselines between patients undergoing and not undergoing primary tumor resection. Further analyses demonstrated that the patients undergoing primary tumor resection had a prolonged OS compared with those not (log-rank P= 0.042). The 2-year and 5-year OS for patients receiving primary tumor resection and EGFR-TKIs was 90.0% and 60.1%.

Conclusions

Primary tumor resection was associated with improved survival in patients with occult intraoperatively-confirmed M1a adenocarcinoma receiving EGFR-TKIs.

Subsolid lesions exceeding 3 centimeters: the ground-glass opacity component still matters

BACKGROUND

Recent studies on the favorable prognosis of ground-glass opacities (GGO) featured lung adenocarcinoma compared with solid nodules were limited to small tumors measuring ≤3.0 cm. This study aimed to investigate whether GGO component could predict better prognosis in patients with large subsolid lesions exceeding 3cm compared with small solid nodules within the same clinical T category.

METHODS

From 2010 to 2015, a total of 1010 patients with completely resected clinical N0 lung adenocarcinoma were enrolled, including 860 solid lesions and 150 subsolid lesions exceeding 3cm. To analyze the prognostic significance of GGO component, propensity score matching adjusting solid component size was performed.

RESULTS

After propensity score matching, 144 pairs of patients were finally analyzed. The mean size of the solid component was 23.7mm in the GGO group and 24.4mm in the solid group(p=0.450). The GGO group had significantly better overall survival and recurrence-free survival (p=0.011 and p=0.003, respectively), which were also validated in patients with solid-predominant lesions. Subgroup analysis showed the GGO group was associated with better prognosis in each clinical T category.

CONCLUSIONS

The prognosis of patients with GGO lesions exceeding 3cm was better than that of patients with small solid lesions even within the same clinical T category. Clinical T classification incorporating GGO component may provide better prognostic prediction for patients with lung cancer exceeding 3cm.

Extent of mediastinal nodal dissection in stage I non-small cell lung cancer with a radiological pure-solid appearance

BACKGROUND

Radiological pure-solid lung cancer denotes a high invasive nature compared to one that is part-solid. Mediastinal lymph nodal dissection (mLND) is a standard surgical procedure for nodal management in lung cancer surgery, however, the prognostic impact of the extent of mLND in pure-solid lung cancer is still unknown.

METHODS

We reviewed 459 patients with c-stage I radiological pure-solid lung cancer that underwent pulmonary lobectomy with mLND. Pure-solid was defined as a tumor showing only a consolidation without any ground glass opacity. The extent of mLND was classified into lobe-specific (L-mLND) and systematic (S-mLND). Prognostic significance of mLND was assessed by a multivariable analysis using propensity-score matching. Survivals were calculated by Kaplan-Meier methods using log-rank test.

RESULTS

Pathological nodal metastasis was found in 127 (27.6%) patients (hilar: 52 (11.3%), mediastinal: 75 (16.3%)). L-mLND was performed in 278 (61%) patients. A multivariable analysis did not show the survival difference for the extent of mLND (p = 0.266). The 5-year overall survival (OS) was not significantly different between S-mLND and L-mLND (74.3% vs. 72.7%, p = 0.712), which was similar even in 114 propensity-score matched pairs (78.8% vs. 79.9%, p = 0.665). While S-mLND showed a trend for survival benefit compared to L-mLND provided that the tumor showed higher standardized uptake value (SUVmax) (5y-OS: 70.0% vs. 59.2%, p = 0.093).

CONCLUSIONS

Prognostic impact of L-mLND was similar to S-mLND in c-stage I radiological pure-solid lung cancers in the propensity-score matched comparison. Among them, higher SUVmax value might be a promising indicator to decide the extent of mediastinal lymphadenectomy.

Clinical impact and utility of positron emission tomography on occult lymph node metastasis and survival: radical surgery for stage I lung cancer

OBJECTIVE

The surgical result of early-staged lung cancer is not satisfactory due to unexpected postoperative lymph node metastasis and recurrence. This study aimed to investigate which preoperative factors-including the standard uptake value max (SUV_max) of positron emission tomography-could predict occult lymph node metastasis and survival.

METHODS

We retrospectively analyzed data from 598 patients with clinical stage I lung cancer who underwent surgery, and examined their preoperative clinical characteristics.

RESULTS

A total of 1586 patients had surgery for primary lung cancer between 2006 and 2019; 598 patients with clinical stage I lung cancer were the study inclusion; occult lymph node metastasis was detected in 102 (17.1%). Univariable and multivariable analyses showed that SUV_max ≥ 3 (P < 0.001), clinical invasive tumor size ≥ 2 cm (P = 0.009), and carcinoembryonic antigen > 5 (P = 0.03) were associated with significant risk factors rated (%) for occult lymph node metastasis, as follows: high-risk group (three factors), moderate-risk group (two factors) and low-risk group (one factor or none) corresponding to 32.2 (28/87), 22.8 (41/180) and 7.3 (19/262), respectively (P < 0.001). The 5-year overall survival rates (%) of patients without lymph node metastasis holding SUV_max 6 or over were as poor as those of patients with lymph node metastasis (72.0% vs 64.1%; P = 0.56).

CONCLUSIONS

We might consider wedge resection or segmentectomy, omitting lymphadenectomy, for the low-risk group; adjuvant therapy is indicated for patients without lymph node metastasis having SUV_max 6 or over.

Clinical features and prognosis of clinical N0 non-small cell lung cancer exceeding 30 mm

OBJECTIVES

This study aimed to determine the characteristics, ground glass opacity ratio and prognosis of patients with clinical N0 non-small cell lung cancer tumours exceeding 30 mm in size.

METHODS

Patients with clinical N0 non-small cell lung cancer and total tumour size >30 mm on preoperative computed tomography who underwent complete resection with lobectomy between January 2007 and December 2017 were included. The patients were divided into three groups: pure solid tumour, low ground glass opacity ratio (1-39%) tumour and high ground glass opacity ratio (≥40%) tumour. The cut-off line was determined based on the recurrence rate for every 10% ground glass opacity ratio.

RESULTS

Among the 227 study patients, 129 (56.8%) had a pure solid tumour, 54 (23.8%) had a low ground glass opacity ratio tumour and 44 (19.4%) had a high ground glass opacity ratio tumour. Three-year recurrence-free survival was significantly shorter in patients with a pure solid tumour (57.4%) than in patients with a low ground glass opacity ratio (74.5%; P = 0.009) or a high ground glass opacity ratio tumour (92.1%; P < 0.001). Multivariable analysis showed that ground glass opacity ratio was a significant independent prognostic factor for recurrence-free survival (hazard ratio, 0.175; P = 0.037).

CONCLUSION

Pure solid tumours comprised a large proportion of non-small cell lung cancer tumours >30 mm in size and their prognosis was poor. The presence of ground glass opacity and their relative proportion affect prognosis in patients with clinical N0 non-small cell lung cancer tumours >30 mm in size, similar to those with small-sized tumours.

Segmentectomy vs Lobectomy for Clinical Stage IA Lung Adenocarcinoma With Spread Through Air Spaces

BACKGROUND

This study aimed to investigate the prognosis after segmentectomy as compared with lobectomy for small-sized lung adenocarcinoma with spread through air spaces (STAS).

METHODS

This retrospective study included 609 patients who underwent lobectomy or segmentectomy with lymph node dissection for clinical stage IA lung adenocarcinoma between April 2011 and March 2020 at Hiroshima University Hospital. Patient characteristics and prognosis after segmentectomy and lobectomy were investigated.

RESULTS

STAS was detected in 293 patients (48.1%). The recurrence-free survival (RFS) rate was significantly worse with STAS-positive adenocarcinoma than with STAS-negative adenocarcinoma both in patients who underwent lobectomy (5-year RFS, 68.2% vs 90.2%; P < .001) and in patients who underwent segmentectomy (5-year RFS, 81.3% vs 93.0%; P = .003). Among the patients with STAS, there was no significant difference in RFS between patients who underwent lobectomy (5-year RFS, 68.2%) and those who underwent segmentectomy (5-year RFS, 81.3%; P = .225). In a multivariable analysis using propensity score to adjust clinical patient characteristics, segmentectomy was not found to be an independent prognostic factor of RFS (hazard ratio 0.732, P = .326) among patients with STAS. Among the patients with STAS, only 1 patient (1%) with insufficient resection margin (0.5 mm) had local recurrence and 1 patient (1%) with invasive mucinous adenocarcinoma had recurrence in preserved lobe after segmentectomy.

CONCLUSIONS

Spread through air spaces was a poor prognostic factor in patients with clinical stage IA lung adenocarcinoma. Prognosis after segmentectomy was comparable with that of lobectomy in lung adenocarcinoma with STAS without increasing locoregional recurrence.

Long-Term Outcomes After Sublobar Resection Versus Lobectomy in Patients With Clinical Stage IA Lung Adenocarcinoma Meeting the Node-Negative Criteria Defined by High-Resolution Computed Tomography and [18F]-Fluoro-2-Deoxy-d-Glucose Positron Emission Tomography

PURPOSE

To evaluate long-term outcomes after sublobar resection for patients with clinical stage IA lung adenocarcinoma who met our proposed node-negative (N0) criteria, namely solid component size < 0.8 cm on high-resolution computed tomography (HRCT) or a maximum standardized uptake value (SUV_max) of < 1.5 on [¹⁸F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT).

PATIENTS AND METHODS

Between April 2006 and December 2010, a total of 347 patients with clinical stage IA lung adenocarcinoma underwent complete resection in two medical centers. Long-term outcomes of patients with disease that met the N0 criteria after sublobar resection were evaluated.

RESULTS

The disease of 201 patients (57.9%) met the N0 criteria. Meeting N0 criteria was significantly associated with low-grade adenocarcinoma subtype (P < .001) and absence of lymphatic invasion (P < .001), vascular invasion (P < .001), and pleural invasion (P < .001). One patient (0.5%) had lymph node metastasis. The median follow-up period was 86.1 months. There was a significant difference in the overall survival (OS) rates between patients with disease that met the N0 criteria (5-year OS, 93.9%; 10-year OS, 90.3%) and disease that did not (5-year OS, 81.5%; 10-year OS, 64.3%; P < .001). Among patients with disease that met the N0 criteria, there was no significant difference in the OS between those who underwent lobectomy (5-year OS, 94.3%; 10-year OS, 92.6%) and those who underwent sublobar resection (5-year OS, 93.8%; 10-year OS, 89.3%; P = .64).

CONCLUSIONS

Sublobar resection of clinical stage IA lung adenocarcinoma is feasible in selected patients with disease that meets the N0 criteria, with excellent long-term survival.

New T1 classification

The IASLC staging and Prognostic Factor Committee proposed new changes to the descriptors for the 8th edition of the Tumour Node Metastasis Staging for Lung Cancer. The T1 descriptor changes include (1) T1 tumours are subclassified into T1a (< 1 cm), T1b (> 1 to < 2 cm), T1c (> 2 to < 3 cm). The corresponding changes are introduced to the overall staging: T1aN0M0 = Stage IA1; T1bN0M0 = Stage IA2; T1cN0M0 = Stage IA3. (2) The introduction of the pathological entities Adenocarcinoma-In-Situ (AIS), Minimally Invasive Adenocarcinoma, and Lepidic Predominant Adenocarcinoma. The corresponding changes on the T descriptor are as follows: Adenocarcinoma-in situ is coded as Tis (AIS); Minimally Invasive Adenocarcinoma is coded as T1a(mi). In this review, the basis for these changes will be described, and the implications on clinical practice will be discussed.

Meta-analysis of comparing part-solid and pure-solid tumors in patients with clinical stage IA non-small-cell lung cancer in the eighth edition TNM classification

Objective: The aim of the study was to compare the prognoses between part-solid and pure-solid tumors for clinical stage IA non-small-cell lung cancer (NSCLC) patients in the eighth edition TNM classification.

Methods: We searched the literature in PubMed and Web of Science for all eligible articles published before November 31, 2018. The pooled data included overall survival (OS), disease-free survival (DFS) and recurrence-free survival (RFS). The hazard ratio (HR) of OS (pure-solid/part-solid) was used as the measure of differential effects. Pure-solid or part-solid tumors in all studies included were matched according to the solid component size or according to the eighth edition TNM classification.

Results: Seven studies including 2,037 patients with c-stage IA NSCLC were pooled in the meta-analysis. Patients with pure-solid tumors had significantly poorer OS (HR 1.69, 95% CI 1.21‒2.35, P=0.002), DFS (HR 1.27, 95% CI 1.07‒1.51, P=0.006) and RFS (HR 1.74, 95% CI 1.08‒2.80, P=0.020). In subgroup analyses, when the meta-analysis was limited to T1a-1b (≤2 cm) lung cancer, the prognosis for pure-solid tumors was inferior to that for part-solid tumors regarding both OS and RFS. In adenocarcinoma subgroup, there was no difference between the two groups in terms of OS and RFS, but we detected a meaningful difference in DFS.

Conclusion: Part-solid tumors may have a better prognosis than pure-solid tumors in clinical stage IA patients according to the eighth edition TNM classification, and similar results were found for the T1a-1b (≤2 cm) subgroup. There were no substantial differences in OS and RFS between two groups in lung adenocarcinoma. However, we detected a meaningful difference in DFS, which might also suggest a superior prognosis for part-solid tumors. We propose that the part-solid and pure-solid tumors in the same T component category be considered separately.

Pathologic T Descriptor of Nonmucinous Lung Adenocarcinomas Now Based on Invasive Tumor Size: How Should Pathologists Measure Invasion?

OBJECTIVES

The eighth edition of the American Joint Committee on Cancer staging manual now stratifies nonmucinous lung adenocarcinomas (nmLACAs) by the size of the invasive component only. This is determined by direct gross or microscopic measurement; however, a calculated invasive size based on the percentage of invasive growth patterns has been proposed as an alternative option.

METHODS

To compare radiologic with different pathologic assessments of invasive tumor size, we retrospectively reviewed a cohort of resected nmLACAs with a part-solid appearance on computed tomography (CT) scan (n = 112).

RESULTS

The median direct microscopic pathologic invasive measurements were not significantly different from the median calculated pathologic invasive measurements; however, the median CT invasive measurements were 0.26 cm larger than the median direct pathologic measurements (P < .001).

CONCLUSIONS

Our results show that pathologic calculated invasive tumor measurements are comparable to direct microscopic measurements of invasive tumor, thereby supporting the recommendation for use of calculated invasive tumor size by the pathologist if necessary.

Identification of SPP1 as a promising biomarker to predict clinical outcome of lung adenocarcinoma individuals

We identified and investigated the prognostic value of secreted phosphoprotein 1 (SPP1) in lung adenocarcinoma (LUAD) patients and evaluate the relationship between the SPP1 expression level and clinical characteristics. First, SPP1 was identified through four LUAD datasets in GEO database and validated by the TCGA database. Then a total of 149 lung adenocarcinoma patients were included, as well as their clinicopathological characteristics collected in the study. The expression levels of SPP1 and adjacent normal tissues were assessed by immunohistochemistry. The association between SPP1 and its prognostic value was systematically evaluated. Results showed high SPP1 level predicted poorer LUAD survival by univariate Cox analysis (P = 0.017), and the multivariate result was also significant (P = 0.021). Subgroup analysis suggested the prognostic value of SPP1 was significant in stage T1 (log rank P = 0.011), stage N0 (log rank P = 0.046) and stage N1 (log rank P = 0.009) patients. After including these markers into a nomogram, the Harrell's C-index of the nomogram was 0.694. In summary, our findings suggest that SPP1 is an independent biomarker with prognostic significance in LUAD.

BRMS1 Expression in Surgically Resected Lung Adenocarcinoma Predicts Future Metastases and Is Associated with a Poor Prognosis

INTRODUCTION

Expression of breast cancer metastasis suppressor 1 gene (BRMS1) is decreased in NSCLC cells and tumors. We hypothesized that intratumoral breast cancer metastasis suppressor 1 (BRMS1) expression is associated with lung adenocarcinoma (LUAD) histologic subtypes and overall survival (OS) and disease-free survival (DFS) in patients undergoing resection for early-stage LUAD.

METHODS

Patients (N = 1030) who underwent complete resection for LUAD with tissue available for histologic evaluation were identified. Tissue microarrays were constructed, and immunostaining was performed and scored for intensity of BRMS1 expression. OS and DFS were estimated (by the Kaplan-Meier method) and compared between groups (by the log-rank test), stratified by stage. Hazard ratios (HRs) for hazard of death and recurrence were estimated using univariable and multivariable Cox proportional hazards models. OS and DFS nomograms were created, and model performance was examined.

RESULTS

Intratumoral BRMS1 expression was high in 632 patients (61%) and low in 398 (39%). Low BRMS1 expression was associated with higher pathologic T stage (p = 0.001), larger tumor size (p ≤ 0.0001), greater lymphatic (p = 0.032) and vascular (p = 0.001) invasion, LUAD histologic subtype (p = 0.001), and intermediate and high architectural tumor grade (p = 0.003). Low BRMS1 expression was an independent predictor of worse OS (HR = 1.35, 95% confidence interval: 1.10-1.65, p = 0.004) and DFS (HR = 1.27, 95% confidence interval: 1.05-1.54, p = 0.012). OS and DFS nomograms showed excellent predictive performance based on discrimination and calibration.

CONCLUSIONS

Among patients with surgically resected LUAD, OS and DFS were significantly worse in cases with low intratumoral BRMS1 expression. Our findings suggest that BRMS1 is an independent biomarker with prognostic significance in surgically resected LUAD.

Risk factors of lymph node metastasis in lung squamous cell carcinoma of 3 cm or less in diameter

Through literature review we cannot find an efficient risk factor of lymph node metastasis in lung squamous cell carcinoma (SCC). This study aimed to investigate the risk factors of pathological lymph node status in patients with lung SCC of 3 cm or less in diameter, to provide some reference for the fellow surgeons in the decision of operative option.In total, we analyzed 154 patients with lung SCC of 3 cm or less in diameter who underwent lobectomy or bilobectomy or pneumonectomy with systematic lymph node dissection. The relationship between lymph node status and clinical characteristics were examined.Lymph node metastases were present in 48 patients (31.2%) of the study subjects. Multivariate analysis indicated that, age <60 years old (P = .007), tumor location of central-type (P = .003), tumor long axis >2 cm but ≤3 cm (P = .047) were associated with lymph node metastasis, and their odd ratios (OR) were 3.120, 3.359, and 5.196, respectively. Group analysis of the 74 peripheral lung SCC showed that those with the tumor long axis ≤2 cm had a lower rate of lymph node metastasis (7.9% vs 27.8%, P = .025).Age <60 years old, tumor location of central-type, and tumor long axis >2 cm but ≤3 cm are risk factors of lymph node metastasis in lung SCC. Systematic lymph node dissection or sampling is recommended when tumor central-type location and/or long axis >2 cm in lung SCC are present.

Dynamic prognostication using conditional survival analysis for patients with operable lung adenocarcinoma

PURPOSE

To evaluate conditional survival among patients with surgically resected stage I-IIIa lung adenocarcinoma and identify changes in prognostic contributions for various prognostic factors over time.

PATIENTS AND METHODS

We performed conditional survival analysis at each t0 (=0, 1, 2, 3, 4, 5 years) for 723 consecutive patients who underwent surgical resection for lung adenocarcinoma, stratified by various clinico-demographic features, as well as pathologic and imaging (tumor-shadow disappearance ratio [TDR] on CT and maximum standardized uptake value [SUVmax] on PET) characteristics. Uni- and multivariableCox regression analyses were performed to evaluate relationships between those variables and conditional survival.

RESULTS

Three-year conditional overall survival (OS) and disease-free survival (DFS) were 92.12% and 75.51% at baseline, but improved steadily up to 98.33% and 95.95% at 5 years after surgery. In contrast to demographic factors, pathologic (stage, subtype, pathologic grade and differentiation) and radiologic factors (TDR and SUVmax) maintained a statistically significant association with subseqeunt 3-year OS until 3 years after surgery. According to the multivariableanalysis, high SUVmax and low TDR value were independent predictors of subsequent 3-year OS and DFS at baseline, 1 and 2 years after surgery, respectively.

CONCLUSION

Our findings based on CS provide theoretical background for clinicians to plan longer period of surveillance following lung adenocarcinoma resection in survivors with preoperatively high SUVmax and low TDR on PET-CT and chest CT, respectively.

Role of CT and PET Imaging in Predicting Tumor Recurrence and Survival in Patients with Lung Adenocarcinoma: A Comparison with the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society Classification of Lung Adenocarcinoma

INTRODUCTION

Recently, a new lung adenocarcinoma classification scheme was published. The prognostic value of this new classification has not been elaborated together with the value of imaging biomarkers including computed tomography (CT) and positron emission tomography (PET).

METHODS

We reviewed pathologic specimens and imaging characteristics of primary tumors from 723 consecutive patients who underwent surgical resection for lung adenocarcinoma. On pathology, the predominant histologic subtype and pattern group were quantified. Tumor-shadow disappearance ratio (TDR) on CT and maximum standardized uptake value (SUVmax) on PET were assessed. The relationships between those variables and survival (overall survival [OS] and disease-free survival) were analyzed by using Kaplan-Meier curves and Cox regression analyses.

RESULTS

The median follow-up period was 3.8 years. There were 137 patients (19%) with recurrence and 167 patients (23%) with metastasis after surgical resection. Among 723 patients, 35 patients (4.8%) had adenocarcinoma in situ, 34 patients (4.7%) had minimally invasive adenocarcinoma, 125 patients (17.3%) had lepidic predominant, 314 patients (43.4%) had acinar predominant, 65 patients (9.0%) had papillary predominant, 23 patients (3.2%) had micropapillary predominant, 113 patients (15.6%) had solid predominant, and 14 patients (1.9%) had variant adenocarcinomas. OS and disease-free survival rates were significantly different according to TDR on CT and SUVmax on PET, predominant subtypes, and pattern groups. On multivariate analysis, the SUVmax (p < 0.001), TDR (p = 0.038), and pattern group (p = 0.015) were independent predictors of OS.

CONCLUSIONS

TDR on CT, SUVmax on PET, and the new histologic classification schemes appear to be promising parameters for the prognostic stratification of patients with lung adenocarcinomas, allowing for the triage of patients who necessitate further staging workup and adjuvant therapy.

The IASLC Lung Cancer Staging Project: Proposals for Coding T Categories for Subsolid Nodules and Assessment of Tumor Size in Part-Solid Tumors in the Forthcoming Eighth Edition of the TNM Classification of Lung Cancer

This article proposes codes for the primary tumor categories of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) and a uniform way to measure tumor size in part-solid tumors for the eighth edition of the tumor, node, and metastasis classification of lung cancer. In 2011, new entities of AIS, MIA, and lepidic predominant adenocarcinoma were defined, and they were later incorporated into the 2015 World Health Organization classification of lung cancer. To fit these entities into the T component of the staging system, the Tis category is proposed for AIS, with Tis (AIS) specified if it is to be distinguished from squamous cell carcinoma in situ (SCIS), which is to be designated Tis (SCIS). We also propose that MIA be classified as T1mi. Furthermore, the use of the invasive size for T descriptor size follows a recommendation made in three editions of the Union for International Cancer Control tumor, node, and metastasis supplement since 2003. For tumor size, the greatest dimension should be reported both clinically and pathologically. In nonmucinous lung adenocarcinomas, the computed tomography (CT) findings of ground glass versus solid opacities tend to correspond respectively to lepidic versus invasive patterns seen pathologically. However, this correlation is not absolute; so when CT features suggest nonmucinous AIS, MIA, and lepidic predominant adenocarcinoma, the suspected diagnosis and clinical staging should be regarded as a preliminary assessment that is subject to revision after pathologic evaluation of resected specimens. The ability to predict invasive versus noninvasive size on the basis of solid versus ground glass components is not applicable to mucinous AIS, MIA, or invasive mucinous adenocarcinomas because they generally show solid nodules or consolidation on CT.

The Prognostic Impact of Tumor Volume in Patients with Clinical Stage IA Non-Small Cell Lung Cancer

INTRODUCTION

Tumor volume promises to be an important factor for predicting the prognosis of patients with non-small cell lung cancer (NSCLC).

METHODS

A total of 255 patients who underwent curative surgical resection for clinical stage IA NSCLC were included. We performed semiautomated measurement of the whole tumor volume and the volume of the solid part (referred to as the solid part volume) from a volumetric analysis of chest three-dimensional computed tomography scans using the SYNAPSE VINCENT imaging software program (Fujifilm Medical, Tokyo, Japan). We evaluated the relationships among tumor size, tumor volume, and survival.

RESULTS

The mean whole tumor size, the ratio of the maximum diameter of consolidation to the maximum tumor diameter (CTR), the whole tumor volume, and the solid part volume were 20 mm (range 0-30 mm), 0.84 (range 0-1.0), 3080 mm(3) (range 123-17509 mm(3)), and 2032 mm(3) (0-12466 mm(3)), respectively. The receiver operating characteristic area under the curve for the whole tumor size, CTR, whole tumor volume, and solid part volume used to identify recurrence were 0.60, 0.68, 0.58, and 0.69, respectively. A univariate analysis revealed that the whole tumor size, CTR, whole tumor volume, and solid part volume were associated with disease-free survival (DFS). A multivariate analysis of these factors identified the solid part volume to be the only independent factor for the prediction of DFS.

CONCLUSIONS

The whole tumor volume and the solid part volume were associated with DFS. In particular, the solid part volume was a very useful factor for predicting prognosis in clinical stage IA NSCLC.

The prognostic value of tumor shadow disappearance rate on integrated PET/CT evaluation of solitary pulmonary nodules with low glucose metabolism

OBJECTIVE

This study aimed to determine the prognostic value of the tumor shadow disappearance rate (TDR) on integrated PET/computed tomography (PET/CT) evaluation of solitary pulmonary nodules (SPNs) with low glucose uptake.

MATERIALS AND METHODS

From January 2008 to September 2010, 99 patients who underwent fluorine-18 fluorodeoxyglucose PET (F-FDG-PET)/CT scanning for the evaluation of SPNs with a maximum standardized uptake value (SUVmax) below 2.75 (2.5+10%) were retrospectively reviewed. Among the 99 SPNs from these patients, 67 were malignant and 32 were benign, based on surgical pathology. Differences in baseline characteristics between the two groups were examined by means of the independent t-test, the Mann-Whitney U-test, and the χ-test. To test the efficacy of TDR for determining malignancy, the sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and positive and negative likelihood ratios (LR+ and LR-, respectively) with 95% confidence intervals were calculated using the pathological test as the gold standard.

RESULTS

Patients with malignant nodules were older than those with benign nodules (64.5 vs. 55.1 years, respectively, P<0.001) and had higher TDRs (0.8 vs. 0.3, respectively, P<0.001). The optimal cutoff point for the TDR was 0.4886 where the sensitivity, specificity, positive predictive value, and negative predictive value were 0.851, 0.844, 0.919, and 0.730, respectively, and the LR+ and LR- were 5.443 and 0177, respectively. A significant negative correlation between TDR and SUVmax was found only in the malignant group.

CONCLUSION

The diagnostic value of TDR complements the PET/CT evaluation of SPNs with a low F-FDG uptake.

Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS)

Due to advances in the understanding of lung adenocarcinoma since the advent of its 2004 World Health System classification, an international multidisciplinary panel [sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS)] has recently updated the classification system for lung adenocarcinoma, the most common histologic type of lung cancer. Here, we summarize and highlight the new criteria and terminology, certain aspects of its clinical relevance and its potential treatment impact, and future avenues of research related to the new system.

Role of FDG-PET/CT in prediction of underestimation of invasive breast cancer in cases of ductal carcinoma in situ diagnosed at needle biopsy

BACKGROUND

The aim of this study was to evaluate the significance of FDG-PET/CT for predicting the underestimation of invasive breast cancer in cases of DCIS at needle biopsy.

PATIENTS AND METHODS

Of 83 consecutive cases with diagnoses of DCIS at primary needle biopsy who underwent curative surgery between 2010 and 2013, the association between the SUVmax on FDG-PET/CT before excision and the underestimation of invasive breast cancer was examined.

RESULTS

There were 29 (34.9%) cases diagnosed to have invasive breast cancer at excision. Receiver operating characteristics curve analysis showed the cutoff value of the SUVmax to predict underestimation of invasive breast cancer was 1.6. The rates of underestimation were 61.5% for patients with a tumor of SUVmax > 1.6 and 11.4% for patients with a tumor of SUVmax ≤ 1.6 (P < .001). A high value of SUVmax was significantly associated with symptomatic presentation (P < .001), palpability (P < .001), mass formation (P = .013), high Breast Imaging Reporting and Data System category (P = .011), and core needle biopsy (P = .007). In multivariate analysis, high SUVmax was only a significant predictive factor of underestimation of invasive breast cancer (hazard ratio, 11.7; 95% confidence interval, 3.70-37.0; P < .001).

CONCLUSION

SUVmax on FDG-PET/CT is useful for predicting the underestimation of invasive breast cancer in cases of DCIS at needle biopsy.

Segmentectomy versus lobectomy for clinical stage IA lung adenocarcinoma

BACKGROUND

Despite the increasing prevalence of the early discovery of small-sized non-small cell lung cancers (NSCLCs), particularly adenocarcinoma, sublobar resection has not yet gained acceptance for patients who can tolerate lobectomy.

METHODS

We compared the outcomes of segmentectomy (n=155) and lobectomy (n=479) in 634 consecutive patients with clinical stage IA lung adenocarcinoma and in propensity score-matched pairs. Those who had undergone wedge resection were excluded.

RESULTS

The 30-day postoperative mortality rate in this population was zero. Patients with large or right-sided tumors, high maximum standardized uptake value (SUVmax), pathologically invasive tumors (with lymphatic, vascular, or pleural invasion), and lymph node metastasis underwent lobectomy significantly more often. Three-year recurrence-free survival (RFS) was significantly higher after segmentectomy compared to lobectomy (92.7% vs. 86.9%, P=0.0394), whereas three-year overall survival (OS) did not significantly differ (95.7% vs. 94.1%, P=0.162). Multivariate analyses of RFS and OS revealed age and SUVmax as significant independent prognostic factors, whereas gender, tumor size and procedure (segmentectomy vs. lobectomy) were not. In 100 propensity score-matched pairs with variables adjusted for age, gender, tumor size, SUVmax, tumor location, the three-year RFS (90.2% vs. 91.5%) and OS (94.8% vs. 93.3%) after segmentectomy and lobectomy respectively were comparable.

CONCLUSIONS

Segmentectomy with reference to SUVmax should be considered as an alternative for clinical stage IA adenocarcinoma, even for low-risk patients.

Segmentectomy for clinical stage IA lung adenocarcinoma showing solid dominance on radiology

OBJECTIVES

This study aimed to compare prognosis after segmentectomy and after lobectomy for radiologically determined solid-dominant clinical stage IA lung adenocarcinoma.

METHODS

From a multicentre database of 610 consecutive patients with clinical stage IA lung adenocarcinoma who underwent complete resection after preoperative high-resolution computed tomography (HRCT) and F-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), 327 patients with a radiologically determined solid-dominant tumour (solid component on HRCT ≥50%) who underwent lobectomy (n = 286) or segmentectomy (n = 41) were included.

RESULTS

No significant difference existed in recurrence-free survival (RFS) between the lobectomy and segmentectomy groups (3-year RFS, 84.4 vs 84.8%, respectively; P = 0.69). There was no significant difference in recurrence pattern between these two groups (local, 5.6 vs 7.3%, P = 0.72; distant, 9.1 vs 4.9%, P = 0.55, respectively). Even in patients with pure solid tumours, no significant difference was observed in RFS between lobectomy and segmentectomy groups (3-year RFS, 76.8 vs 84.7%, respectively; P = 0.48), as well as in those with a mixed ground-glass opacity tumour (3-year RFS, 91.0 vs 85.0%, respectively; P = 0.60). Multivariate Cox analysis demonstrated that solid tumour size on HRCT (P = 0.048) and maximum standardized uptake value (SUVmax) on FDG-PET/CT (P < 0.001), not the surgical procedure (P = 0.40), were independent prognostic factors for RFS.

CONCLUSIONS

RFS depends on solid tumour size on HRCT and SUVmax on FDG-PET/CT, rather than on the surgical procedure, in patients with radiologically detected solid-dominant clinical stage IA lung adenocarcinoma. Patient prognosis is similar after lobectomy and after segmentectomy for solid-dominant tumour.